I am very disappointed that I cannot efile an amended return for 2020. The IRS makes it very clear that "you can now file the Form 1040-X, Amended U.S. Individual Income Tax Return electronically using available tax software products." So this isn't an IRS limitation, but a TurboTax one.
Worse is that there isn't a clear message in TurboTax desktop to say why it can't be done. It just won't let you put in today's date as the date signature. It should just simply say that TurboTax lacks the ability to do it.
Amended Return Frequently Asked Questions | Internal Revenue Service (irs.gov)
